The present invention relates to an apparatus and method for having a server hold obfuscated data. The present invention particularly relates to an apparatus and method for having a server hold obfuscated data obtained by obfuscating data as a result of converting a character code included in the data.
Recently, online storage services for renting a storage space of a server to receive and hold user data in trust via the Internet have been widely used. Such online storage services are provided on the premise that the service provider is trustworthy and spreading belief is that there is no problem if data is held intact on the server. Therefore, techniques for protecting data held on a server on the faith of the server side have been proposed in the past. Known literature discloses a technique for holding text with various contents posted on a web page to provide the text readable only on an URL that designates encrypted text and makes the encrypted text indecipherable on the other URLs.
On the other hand, in an online storage service using a SaaS (Software as a Service) based application, a service provider may be untrusted. In such a case, when data held on a server contains confidential information such as business secrets and personal information, there arises a problem that these pieces of information leak out to the service provider. Therefore, techniques for preventing confidential information held on the server from leaking out to the service provider are also proposed.